Wisconsin Officials Investigating Massive Fish Kill of Over 600 Trout

by Lauren Boisvert

In an area of Wisconsin known for its fly fishing, there’s been a massive fish kill that claimed hundreds of trout. The Wisconsin Department of Natural Resources has opened an investigation into the massive die-off on Isabelle Creek, which flows through Pierce County. The numbers came in at 600 trout dead plus a variety of prey fish (this is a large number for Isabelle Creek, but it pales in comparison to this Minnesota die-off). Since August 17, the WDNR has been on-site multiple times at the creek. The WDNR first put out a statement on the die-off on August 25.

At a Glance

  • Since August 17, the Wisconsin Department of Natural Resources has been investigating a massive fish kill on Isabelle Creek in Pierce County
  • The WDNR reported 600 trout dead and a variety of dead prey fish species
  • This extreme die-off is still being investigated

Wisconsin Officials Report Large-Scale Fish Kill in Small Stream

“DNR staff observed dead fish in Isabelle Creek flowing south along County Road C in Ellsworth,” stated a press release from the Wisconsin Department of Natural Resources. “So far, DNR staff have observed over 600 dead trout and a variety of dead forage fish species in Isabelle Creek. DNR staff has been onsite several times since August 17.”

There is currently no additional information on this die-off. The incident is still under investigation, and WDNR will release detail as they emerge.

Wisconsin Locals Feel This Trout Die-Off Will Impact Fishing in Pierce County

River Falls, Wisconsin resident Brian Schubert, of Lund’s Fly Shop, told Field and Stream that this fish kill could significantly affect the fishing and tourism in the area. Lund’s Fly Shop is about 25 miles northwest of tiny Isabelle Creek. Isabelle is usually overshadowed by larger trout waters like Rush River, Trimbelle River, and the 22-mile-long Kinnickinnic River. But, according to locals, Isabelle Creek is the hidden gem of trout fishing. That’s why they’re so worried about this die-off.

“It’s not a really high-density stream,” said Schubert. “For a stream of its size, 600 is a big number. Depending on the area of the stream affected, it could have a very serious impact on the stream’s trout population.” 

According to Schubert, Isabelle Creek is home to brook and brown trout, similar to the larger rivers and streams. Brown trout were once stocked in the rivers and are now naturally reproducing, but the brook trout are a native species.

During the week of August 22, the WDNR also reported another “large-scale fish kill” in the Fox River and Green Bay River. The department did not provide a total number of dead fish. But, it did report that they died of columnaris that mostly affected channel catfish. Columnaris is a bacterial disease that affects freshwater fish. It causes lesions, white spots or patches on the head, fins, or gills, cotton-like lesions specifically in the mouth, and frayed fins.